This Mentored Patient-Oriented Research Career Development Award will prepare the applicant for a career in patient-oriented clinical research in the field of inborn errors of metabolism. Increased recognition and survival in children with metabolic disorders have created a great need for metabolic clinicians trained in clinical research. In particular the cognitive and behavioral profiles of children these children remain largely unexplored and worldwide few clinicians have the requisite skills and training to conduct these studies. The candidate plans to: 1) acquire didactic instruction in clinical research skills as well as familiarity with the fundamentals of cognition and neuropsychology, and 2) complete a mentored clinical research study on attentional dysfunction among children with phenylketonuria (PKU). The candidate's long-term goal is to develop a series of funded clinical investigations to improve biological and psychological outcomes in children with phenylketonuria and other inborn errors of metabolism. The University of Rochester School of Medicine and Dentistry provides a rich environment for conducting clinical research, and recently developed a formal curriculum for training candidates in clinical research. At the completion of the five-year period, the applicant will have the skills necessary to conduct funded clinical research, and the applicant's work will have the potential to contribute significantly to the body of patient-oriented clinical research in the field of inborn errors of metabolism.